gpio: introduce it8761e_gpio driver for IT8761E Super I/O chip (9cc0cb3c) · Commits · e / devices / android_kernel_samsung_universal8895

drivers/gpio/Kconfig

+6 −0

Original line number	Diff line number	Diff line
		@@ -70,6 +70,12 @@ config GPIO_MAX730X

		comment "Memory mapped GPIO expanders:"

		config GPIO_IT8761E
		tristate "IT8761E GPIO support"
		depends on GPIOLIB
		help
		Say yes here to support GPIO functionality of IT8761E super I/O chip.

		config GPIO_PL061
		bool "PrimeCell PL061 GPIO support"
		depends on ARM_AMBA

drivers/gpio/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -22,5 +22,6 @@ obj-$(CONFIG_GPIO_UCB1400) += ucb1400_gpio.o
		obj-$(CONFIG_GPIO_XILINX) += xilinx_gpio.o
		obj-$(CONFIG_GPIO_CS5535) += cs5535-gpio.o
		obj-$(CONFIG_GPIO_BT8XX) += bt8xxgpio.o
		obj-$(CONFIG_GPIO_IT8761E) += it8761e_gpio.o
		obj-$(CONFIG_GPIO_VR41XX) += vr41xx_giu.o
		obj-$(CONFIG_GPIO_WM831X) += wm831x-gpio.o

drivers/gpio/it8761e_gpio.c

0 → 100644

+231 −0

Original line number	Diff line number	Diff line
		/*
		* it8761_gpio.c - GPIO interface for IT8761E Super I/O chip
		*
		* Author: Denis Turischev <denis@compulab.co.il>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License 2 as published
		* by the Free Software Foundation.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; see the file COPYING. If not, write to
		* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
		*/

		#include <linux/init.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/io.h>
		#include <linux/errno.h>
		#include <linux/ioport.h>

		#include <linux/gpio.h>

		#define SIO_CHIP_ID 0x8761
		#define CHIP_ID_HIGH_BYTE 0x20
		#define CHIP_ID_LOW_BYTE 0x21

		static u8 ports[2] = { 0x2e, 0x4e };
		static u8 port;

		static DEFINE_SPINLOCK(sio_lock);

		#define GPIO_NAME "it8761-gpio"
		#define GPIO_BA_HIGH_BYTE 0x60
		#define GPIO_BA_LOW_BYTE 0x61
		#define GPIO_IOSIZE 4
		#define GPIO1X_IO 0xf0
		#define GPIO2X_IO 0xf1

		static u16 gpio_ba;

		static u8 read_reg(u8 addr, u8 port)
		{
		outb(addr, port);
		return inb(port + 1);
		}

		static void write_reg(u8 data, u8 addr, u8 port)
		{
		outb(addr, port);
		outb(data, port + 1);
		}

		static void enter_conf_mode(u8 port)
		{
		outb(0x87, port);
		outb(0x61, port);
		outb(0x55, port);
		outb((port == 0x2e) ? 0x55 : 0xaa, port);
		}

		static void exit_conf_mode(u8 port)
		{
		outb(0x2, port);
		outb(0x2, port + 1);
		}

		static void enter_gpio_mode(u8 port)
		{
		write_reg(0x2, 0x7, port);
		}

		static int it8761e_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
		{
		u16 reg;
		u8 bit;

		bit = gpio_num % 7;
		reg = (gpio_num >= 7) ? gpio_ba + 1 : gpio_ba;

		return !!(inb(reg) & (1 << bit));
		}

		static int it8761e_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
		{
		u8 curr_dirs;
		u8 io_reg, bit;

		bit = gpio_num % 7;
		io_reg = (gpio_num >= 7) ? GPIO2X_IO : GPIO1X_IO;

		spin_lock(&sio_lock);

		enter_conf_mode(port);
		enter_gpio_mode(port);

		curr_dirs = read_reg(io_reg, port);

		if (curr_dirs & (1 << bit))
		write_reg(curr_dirs & ~(1 << bit), io_reg, port);

		exit_conf_mode(port);

		spin_unlock(&sio_lock);
		return 0;
		}

		static void it8761e_gpio_set(struct gpio_chip *gc,
		unsigned gpio_num, int val)
		{
		u8 curr_vals, bit;
		u16 reg;

		bit = gpio_num % 7;
		reg = (gpio_num >= 7) ? gpio_ba + 1 : gpio_ba;

		spin_lock(&sio_lock);

		curr_vals = inb(reg);
		if (val)
		outb(curr_vals \| (1 << bit) , reg);
		else
		outb(curr_vals & ~(1 << bit), reg);

		spin_unlock(&sio_lock);
		}

		static int it8761e_gpio_direction_out(struct gpio_chip *gc,
		unsigned gpio_num, int val)
		{
		u8 curr_dirs, io_reg, bit;

		bit = gpio_num % 7;
		io_reg = (gpio_num >= 7) ? GPIO2X_IO : GPIO1X_IO;

		it8761e_gpio_set(gc, gpio_num, val);

		spin_lock(&sio_lock);

		enter_conf_mode(port);
		enter_gpio_mode(port);

		curr_dirs = read_reg(io_reg, port);

		if (!(curr_dirs & (1 << bit)))
		write_reg(curr_dirs \| (1 << bit), io_reg, port);

		exit_conf_mode(port);

		spin_unlock(&sio_lock);
		return 0;
		}

		static struct gpio_chip it8761e_gpio_chip = {
		.label = GPIO_NAME,
		.owner = THIS_MODULE,
		.get = it8761e_gpio_get,
		.direction_input = it8761e_gpio_direction_in,
		.set = it8761e_gpio_set,
		.direction_output = it8761e_gpio_direction_out,
		};

		static int __init it8761e_gpio_init(void)
		{
		int i, id, err;

		/* chip and port detection */
		for (i = 0; i < ARRAY_SIZE(ports); i++) {
		spin_lock(&sio_lock);
		enter_conf_mode(ports[i]);

		id = (read_reg(CHIP_ID_HIGH_BYTE, ports[i]) << 8) +
		read_reg(CHIP_ID_LOW_BYTE, ports[i]);

		exit_conf_mode(ports[i]);
		spin_unlock(&sio_lock);

		if (id == SIO_CHIP_ID) {
		port = ports[i];
		break;
		}
		}

		if (!port)
		return -ENODEV;

		/* fetch GPIO base address */
		enter_conf_mode(port);
		enter_gpio_mode(port);
		gpio_ba = (read_reg(GPIO_BA_HIGH_BYTE, port) << 8) +
		read_reg(GPIO_BA_LOW_BYTE, port);
		exit_conf_mode(port);

		if (!request_region(gpio_ba, GPIO_IOSIZE, GPIO_NAME))
		return -EBUSY;

		it8761e_gpio_chip.base = -1;
		it8761e_gpio_chip.ngpio = 14;

		err = gpiochip_add(&it8761e_gpio_chip);
		if (err < 0)
		goto gpiochip_add_err;

		return 0;

		gpiochip_add_err:
		release_region(gpio_ba, GPIO_IOSIZE);
		gpio_ba = 0;
		return err;
		}

		static void __exit it8761e_gpio_exit(void)
		{
		if (gpio_ba) {
		gpiochip_remove(&it8761e_gpio_chip);

		release_region(gpio_ba, GPIO_IOSIZE);
		gpio_ba = 0;
		}
		}
		module_init(it8761e_gpio_init);
		module_exit(it8761e_gpio_exit);

		MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
		MODULE_DESCRIPTION("GPIO interface for IT8761E Super I/O chip");
		MODULE_LICENSE("GPL");